Polycrystal diamond sintering body cooling fin

Abstract

The invention relates to the technical field of polycrystalline diamond sintering body cooling fins, and discloses a polycrystalline diamond sintering body cooling fin which is made of PCD, the PCD does not contain cobalt and does not have a bottom, at least one face of the PCD is brazed through copper-titanium alloy, the PCD is coated with copper and is flexibly welded to a semiconductor to be used, and a chip comprises a CPU, a GPU, an IGBT or an HEMT. According to the polycrystalline diamond sintered body cooling fin, diamond copper coating is combined with low thermal expansion rate and high thermal conductivity, the diamond is sintered at high pressure (such as Polycrystalline Diamond or PCD) or vapor deposition (Chemic Vapor Deposition to form PCD) with silicon as a binder, copper coating is brazed through copper-titanium alloy, titanium carbide is generated on the diamond interface through chemical combination, the diamond is firmly grasped, the power or speed is not limited, and the service life of the diamond is prolonged. The practicability is more ideal.

Description

Technical Field

[0001] The invention relates to the technical field of heat sinks, in particular to a polycrystalline diamond sintered body heat sink. Background Art

[0002] The power of semiconductor chip components (such as IGBT, HEMT) or computing speed (such as CPU, GPU) is getting higher and higher, so the chip is getting hotter and hotter, which may cause chip failure or reduce its reliability. Ordinary copper heat sinks have long been unusable. In addition, the thermal expansion rate of metal is much higher than that of semiconductors. The soldering of the two will cause micro cracks on the interface due to frequent temperature rise and fall, which reduces the reliability of the chip. At present, ceramic copper cladding (such as Doubly Bonded Copper or DBC) or even silicone grease TIM can only be used to relieve the interface stress. However, the thermal conductivity of ceramics (such as alumina or silicon nitride) is poor, and TIM is even closer to insulation. The power or speed of chips using ceramic insulation or TIM will be greatly limited. Therefore, there is an urgent need for a polycrystalline diamond sintered heat sink to solve the above technical problems. Summary of the invention

[0003] The purpose of the present invention is to provide a polycrystalline diamond sintered body heat sink. The present invention provides the following technical solution: the polycrystalline diamond sintered body heat sink is made of PCD, the PCD does not contain cobalt and has no bottom.

[0004] As a preferred technical solution of the present invention, at least one side of the PCD is brazed with copper-titanium alloy.

[0005] As a preferred technical solution of the present invention, the PCD copper cladding is used for soft soldering on semiconductors.

[0006] As a preferred technical solution of the present invention, the semiconductor is a power chip or a computing chip.

[0007] As a preferred technical solution of the present invention, the chip includes a CPU, a GPU, an IGBT or a HEMT.

[0008] As a preferred technical solution of the present invention, the method for preparing the polycrystalline diamond sintered body heat sink comprises the following steps:

[0009] Step 1: Cover the top and bottom of the silicon-sintered PCD with titanium foil and copper foil;

[0010] Step 2: Use a vacuum furnace to heat to 1000°C at 10^-5torr and hold the temperature for 20 minutes;

[0011] Step 3: After cooling, take out the PCD and get double-sided copper coating, and the copper is firmly welded with silicon carbide.

[0012] As a preferred technical solution of the present invention, the hardness of the PCD is 8000 HV.

[0013] As a preferred technical solution of the present invention, the thermal conductivity of the PCD is 700 W / mK, which is 8 times that of cemented carbide.

[0014] As a preferred technical solution of the present invention, the friction coefficient of the PCD is generally only 0.2.

[0015] As a preferred technical solution of the present invention, the thermal expansion coefficient of the PCD is 0.9×10^-6~

[0016] ^

[0017] 1.18×10-6.

[0018] Compared with the prior art, the present invention has the following beneficial effects: the polycrystalline diamond sintered heat sink of the present invention combines diamond-copper coating with low thermal expansion coefficient and high thermal conductivity. Diamond is sintered under high pressure (such as Polycrystalline Diamond or PCD) or vapor deposited (Chemical Vapor Deposition into PCD) with silicon as a binder, and the copper coating is brazed with copper-titanium alloy to form titanium carbide at the diamond interface, which firmly grasps the diamond, making power or speed unlimited and more practical. DETAILED DESCRIPTION

[0019] The present application is further described in detail below in conjunction with the embodiments. It is understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for the convenience of description, only the parts related to the invention are shown, and the different types of section lines in the embodiments of the present invention are not marked according to the national standard, and no requirements are made on the materials of the components.

[0020] Please refer to a polycrystalline diamond sintered body heat sink, which is made of PCD. The PCD does not contain cobalt and does not have a bottom.

[0021] Wherein, at least one side of the PCD is brazed with copper-titanium alloy.

[0022] Among them, PCD copper cladding is used for soft soldering on semiconductors.

[0023] Among them, the semiconductor is a power chip or a computing chip.

[0024] Among them, the chips include CPU, GPU, IGBT or HEMT.

[0025] The method for preparing the polycrystalline diamond sintered body heat sink comprises the following steps:

[0026] Step 1: Cover the top and bottom of the silicon-sintered PCD with titanium foil and copper foil;

[0027] Step 2: Use a vacuum furnace to heat to 1000°C at 10^-5torr and hold the temperature for 20 minutes;

[0028] Step 3: After cooling, take out the PCD and get double-sided copper coating, and the copper is firmly welded with silicon carbide.

[0029] Among them, the hardness of PCD is 8000HV.

[0030] Among them, the thermal conductivity of PCD is 700W / mK, which is 8 times that of cemented carbide.

[0031] Among them, the friction coefficient of PCD is generally only 0.2.

[0032] Among them, the thermal expansion coefficient of PCD is 0.9×10^-6~1.18×10^-6.

[0033] It should be noted that diamond-copper cladding combines low thermal expansion and high thermal conductivity. Diamond is sintered under high pressure (such as Polycrystalline Diamond or PCD) or vapor deposited (Chemical Vapor Deposition into PCD) with silicon as a binder, and the copper cladding is brazed with copper-titanium alloy to form titanium carbide at the diamond interface. This firmly grasps the diamond, making power or speed unlimited and more practical.

[0034] Example 1

[0035] PCD sintered with silicon is covered with titanium foil and copper foil on the top and bottom. A vacuum furnace is used to heat it to 1000 degrees C at 10^-5torr and keep the temperature for 20 minutes. After cooling down, it is taken out to obtain PCD with copper on both sides. The copper is firmly soldered with silicon carbide (TiC). Because the high thermal expansion of copper has been limited by the PCD that does not expand much, the thermal expansion rate of the combination is close to that of semiconductor materials (such as silicon or silicon silicide). Therefore, it can be combined with low-temperature (such as 200C) soft soldering (such as silver-tin alloy) without fatigue problems caused by thermal expansion and contraction.

[0036] The contents not described in detail in this specification belong to the prior art known to professionals in this field.

[0037] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A polycrystalline diamond sintered body heat sink, which is made of PCD and is characterized by: PCD does not contain cobalt and does not have a bottom.

2. A polycrystalline diamond sintered body heat sink according to claim 1, characterized in that: At least one side of the PCD is brazed with copper-titanium alloy.

3. The polycrystalline diamond sintered body heat sink according to claim 1, characterized in that: The PCD copper cladding is used for soldering on semiconductors.

4. A polycrystalline diamond sintered body heat sink according to claim 3, characterized in that: The semiconductor is a power chip or a computing chip.

5. The polycrystalline diamond sintered body heat sink according to claim 4, characterized in that: The chip includes a CPU, a GPU, an IGBT or a HEMT.

6. The polycrystalline diamond sintered body heat sink according to claim 1, characterized in that: The method for preparing the polycrystalline diamond sintered body heat sink comprises the following steps: Step 1: Cover the top and bottom of the silicon-sintered PCD with titanium foil and copper foil; Step 2: Use a vacuum furnace to heat to 1000°C at 10^-5torr and hold the temperature for 20 minutes; Step 3: After cooling, take out the PCD and get double-sided copper coating, and the copper is firmly welded with silicon carbide.

7. The polycrystalline diamond sintered body heat sink according to claim 1, characterized in that: The hardness of the PCD is 8000 HV.

8. The polycrystalline diamond sintered body heat sink according to claim 1, characterized in that: The thermal conductivity of the PCD is 700 W / mK, which is 8 times that of cemented carbide.

9. The polycrystalline diamond sintered body heat sink according to claim 1, characterized in that: The friction coefficient of the PCD is generally only 0.

2.

10. The polycrystalline diamond sintered body heat sink according to claim 1, characterized in that: The thermal expansion coefficient of the PCD is 0.9×10^-6 to 1.18×10^-6.